Variety choice is very important and potatoes with greater than 13% starch content are required in countries such as Germany. The higher the starch content, the lower the waste.
Nitrogen is an essential nutrient to fuel canopy growth, however in temperate climates, an excess supply of nitrogen at later stages of growth will keep the crop growing, delaying maturity and may reduce starch content, reducing processing potato crop quality.
Phosphate fertiliser use can influence starch quality. By increasing the tuber phosphate content, the viscosity of the gelatinised starch is also increased and the gelatinisation temperature decreased.
This data shows the relationship between tuber phosphate content and starch quality, as measured by viscosity.